The present invention relates to a structure and a method for mounting a semiconductor device or similar electronic part to the surface of a printed circuit board.
A structure for mounting a semiconductor device is disclosed in, e.g., Japanese Patent Laid-Open Publication No. 8-78474. The structure taught in this document includes a printed circuit board and a chip size package (CSP) or electronic part mounted on the surface of the circuit board. A CSP refers to a semiconductor package having substantially the same size as a semiconductor chip. The circuit board has electrode portions connected to the electrode portions of the CSP by solder bumps. Insulative adhesive fills a gap between the circuit board and the CSP.
However, a problem with the above conventional structure is that bubbles are apt to enter the adhesive when the adhesive is caused to flow into the small gap between the circuit board and the CSP, degrading the firm connection between the circuit board and the CSP. Filling the adhesive without introducing bubbles is particularly difficult when the CSP has a broad area.
Further, the circuit board and CSP have their electrodes connected together by the solder bumps, and the solder bumps are covered with the insulative adhesive. This brings about another problem that at the time of replacement of the CSP, it is difficult to remove the solder bumps and adhesive from the CSP removed from the circuit board and the circuit board. Moreover, to mount a new CSP to the circuit board, there must be repeated the steps of forming solder bumps and filling insulative adhesive. As a result, the replacement of the CSP mounted on the printed circuit board is time- and labor-consuming.